Age-related macular degeneration (AMD) is a degenerative eye disease that affects the macula, which is a photoreceptor-rich area of the central retina that provides detailed vision. AMD results in a sudden worsening of central vision that usually only leaves peripheral vision intact. AMD is the most common form of irreversible blindness in developed countries. The disease typically presents with a decrease in central vision in one eye, followed within months or years by a similar loss of central vision in the other eye. Clinical signs of the disease include the presence of deposits (drusen) in the macula.
Despite being a major public health burden, the etiology and pathogenesis of AMD are still poorly understood. Numerous studies have implicated inflammation in the pathobiology of AMD (Anderson et al. (2002)Am. J. Ophthalmol. 134:411-31; Hageman et al. (2001) Prog. Retin. Eye Res. 20:705-32; Mullins et al. (2000) Faseb J. 14:835-46; Johnson et al. (2001) Exp. Eye Res. 73:887-96; Crabb et al. (2002) Proc. Natl. Acad. Sci. U.S.A. 99:14682-7; Bok, D. (2005) Proc. Natl. Acad. Sci. U.S.A. 102:7053-4). Dysfunction of the complement pathway may induce significant bystander damage to macular cells, leading to atrophy, degeneration, and the elaboration of choroidal neovascular membranes, similar to damage that occurs in other complement-mediated disease processes (Hageman et al. (2005) Proc. Natl. Acad. Sci. U.S.A. 102:7227-32; Morgan and Walport (1991) Immunol. Today 12:301-6; Kinoshita (1991) Immunol. Today 12:291-5; Holers and Thurman (2004) Mol. Immunol. 41:147-52). There may be a strong genetic contribution to the disease. For example, variants in the FBLN6, ABCA4, and APOE genes have been implicated as risk factors. Recently, it was discovered that a variant in the complement factor H gene (CHI), which encodes a major inhibitor of the alternative complement pathway, is associated with increased risk of developing AMD (Haines et al. (2005) Science 308:419-21; Klein et al. (2005) Science 308:385-9; Edwards et al. (2005) Science 308:421-4; Hageman et al. (2005) Proc. Natl. Acad. Sci. U.S.A. 102:7227-32).
Due to the prevalence of the disease and the limited treatment available, methods for identifying subjects at risk for developing AMD are needed.